Update: Looks like Torna the Golden Country's physical version is a proper cartridge release after all

[curl-6]

Update: I phoned Nintendo directly (har har) to ask them what the go was.

The rep I spoke to confessed he didn't know and found it confusing and unclear himself, and said he had to speak to his superiors.

After 5 minutes on hold, he returned to inform me it was "most likely" just a code in a box.